Conventionally, a process of shaping a piezoelectric element such as a crystal oscillator, an electron device, or the like is performed in a manner in which an abrasive and a workpiece material are blended or an abrasive, an ancillary material, and a workpiece material are blended in a processing container, and the processing container is rotated.
For example, in Japanese Patent Application Laid-Open Publication No. 10-217084 (Patent Document 1), a method for manufacturing a rectangular AT vibrating reed is described. In this manufacturing method, an abrasive and rectangular AT vibrating reed are put into a spherical pot, and the spherical pot is rotated on an axis thereof and revolved around in a circular manner, thereby forming an inclination on a planar surface of the rectangular AT vibrating reed.
In addition, for example, in Japanese Patent Application Laid-Open Publication No. 2002-330042 (Patent Document 2), a beveling work method for a crystal oscillator or the like is described. In this work method, in addition to a piezoelectric blank plate of a crystal oscillator or the like and a work abrasive comprising alumina-based loose abrasive grains, a spherical or tabular ancillary material comprising ceramic, a resin material, a crystal material, metal, and the like is put into a work cylinder and the work cylinder is rotated, thereby performing the beveling work for the piezoelectric blank plate.
As described above, in the above-mentioned Publications, the ancillary material is added in order to increase a work efficiency in a process of shaping the piezoelectric element, the electron device, or the like. Note that the conventional tungsten alloy grains and manufacturing method thereof are described in Japanese Patent No. 2987911 (Patent Document 3) and Japanese Patent Application Laid-Open Publication No. 4-308003 (Patent Document 4).    Patent Document 1: Japanese Patent Application Laid-Open Publication No. 10-217084    Patent Document 2: Japanese Patent Application Laid-Open Publication No. 2002-330042    Patent Document 3: Japanese Patent No. 2987911    Patent Document 4: Japanese Patent Application Laid-Open Publication No. 4-308003